High PGL productivity in Bacillus subtilis by optimizing the SD sequence

Abstract

Alkaline polygalacturonate lyase (PGL, EC 4.2.2.2) can catalyze the cleavage of a-1, 4-glycosidic bonds of polygalacturonate by a trans-elimination reaction and generate an unsaturated oligogalacturonates. As the critical enzyme of many environmental friendly processes, alkaline PGL has been widely used in many fields including paper, textile and beverage industries. At present, Bacillus subtilis is an ideal strain for producing PGL, but the yield is too low for industrial production. In this study, the effect of different SD sequences on the production of PGL was comparatively investigated, and the strong SD sequence (AGAGAACAAGGAGGG G) directed efficient PGL secretory expression and increased PGL yield to 264.5 U·mL^-1 with a high productivity. As a result, the PGL yield in B. subtilis was effecively increased and laid the solid foundation for PGL industrial production.